1. Field of the Invention
This invention relates to a speaker enclosure for housing mid-range and high frequency transducers configured to minimize the diffraction that could interfere with wave fronts from its transducers.
2. Related Art
There are many types of speaker enclosures and each type can affect how sound is produced. Within a speaker enclosure is at least one driver (or transducer) that has a vibrating diaphragm for emitting sound waves in front of the cone. A baffle forms the front side of the speaker enclosure and has a wave guide that forms a smooth transition between the cone of the driver and the front side of the speaker enclosure. Moreover, a speaker enclosure may house a combination of drivers, such as mid-range and high frequency drivers, in one unit to keep the combination of drivers in a correct position so that they can work together.
One of the problems associated with a speaker enclosure is a phenomenon known as diffraction. Diffraction interferes with the quality of sound produced by the drivers. For example, a typical baffle may be substantially flat so that the speaker enclosure has a flat face. As the wave front propagates from the driver, it starts from the diaphragm and propagates along the wave guide and then along the outer edge of the speaker enclosure. Beyond the outer edge of the speaker enclosure, the wave front does not have a baffle to sustain the wave front and so it goes into free air. As the wave front transitions from the outer edge of the baffle to free air, there is an abrupt discontinuity to sustain the wave front. Such abrupt discontinuity, however, can cause eddy currents to occur in the wave front. Eddy currents may be generally described as whirl or circular currents of air running contrary to the steady flow of fluid causing a vortex. Eddy currents occur when there is a boundary layer separation between the wave front and the surface that is supporting the wave front. Eddy currents destructively add to the wave front such that the quality of sound is diminished. This phenomenon may be generally described as a diffraction. In particular, diffraction occurs from wave fronts that propagate from high frequency drivers because the velocity of wave fronts are higher, which further induces boundary layer separation to occur. As the velocity of the wave front increases, the momentum of the wave front may overcome the pressure forces holding the wave front to the support surface to cause boundary layer separation.
Another common shortfall of the speaker enclosure is the control of sound waves, both in horizontal and vertical axis. In the horizontal axis, a wide sound disbursement is preferred so that a listener can move from the center position without losing stereo image. In the vertical axis, however, the sound disbursement should be more controlled because listeners are typically limited in their vertical movements. In other words, a listener""s movements are much more limited in the vertical axis than in the horizontal axis. Despite this distinction, speaker enclosures do not control or stabilize the sound waves in the vertical axis in order to improve the quality of sound. Therefore, there is still a need for a speaker enclosure that minimizes diffractions from occurring and provides a more stable or controlled sound disbursement in the vertical axis.
This invention provides a speaker enclosure that is configured to minimize diffractions from occurring. To accomplish this, a portion of the baffle that is adjacent to a high frequency driver may be tapered inward to provide a smooth transition for the wave fronts to propagate from the outer edge of the speaker housing to free air. Providing a smooth transition for the wave fronts minimizes the occurrence of eddy currents so that diffractions do not interfere with the quality of sound from the driver. Moreover, the portion of the baffle that is adjacent to the high frequency driver may be curved and smooth to the outer edge of the baffle to further minimize diffractions from occurring.
To stabilize or control the wave fronts in the vertical axis, the baffle may be elongated in the vertical axis to sustain the wave front in that axis. That is, the elongated baffle in the vertical axis forms a surface that behaves as a wave guide to control and sustain the wave front in the vertical axis to enhance the quality of sound. However, in the horizontal axis, the baffle may be narrower than in the vertical axis so that the wave fronts may disperse more widely in the horizontal axis.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.